Answer:
Date Significance Soviet Union Mission
August 21, 1957 First intercontinental ballistic missile (ICBM) R-7 Semyorka
October 4, 1957 First artificial satellite First signals from space Sputnik 1
November 3, 1957 First dog in orbit (Laika) Sputnik 2
January 31, 1958 First US satellite, detection of Van Allen radiation belts
Explanation:
To determine the Ka of the acid, we can use the equation for the pH of weak acids which is expressed as:
pH = -0.5 log Ka
2.67 = -0.5 log Ka
Ka = 4.571x10^-6
Weak acids are acids that do not dissociate completely in solution. The solution would contain the cations, anions and the acid itself as a compound. Hope this helps.
Answer:
P₂ ≅ 100 atm (1 sig. fig. based on the given value of P₁ = 90 atm)
Explanation:
Given:
P₁ = 90 atm P₂ = ?
V₁ = 18 Liters(L) L₂ = 12 Liters(L)
=> decrease volume => increase pressure
=> volume ratio that will increase 90 atm is (18L/12L)
T₁ = 272 Kelvin(K) T₂ = 274 Kelvin(K)
=> increase temperature => increase pressure
=> temperature ratio that will increase 90 atm is (274K/272K)
n₁ = moles = constant n₂ = n₁ = constant
P₂ = 90 atm x (18L/12L) x (274K/272K) = 135.9926471 atm (calculator)
By rule of sig. figs., the final answer should be rounded to an accuracy equal to the 'measured' data value having the least number of sig. figs. This means P₂ ≅ 100 atm based on the given value of P₁ = 90 atm.
Answer:
Ley.
Explanation:
En la teoría de la ciencia, la regularidad de los procesos en la naturaleza se denomina ley de la naturaleza. Las leyes naturales se diferencian de otras leyes en que los seres humanos no pueden ponerlas en vigor ni anularlas a su discreción. En tal sentido, la composición química del agua es indudablemente una ley natural, en tanto el hombre no puede modificarla sin modificar las características inherentes del agua como tal.
The much of the sample that would remain unchanged after 140 seconds is 2.813 g
Explanation
Half life is time taken for the quantity to reduce to half its original value.
if the half life for Scandium is 35 sec, then the number of half life in 140 seconds
=140 sec/ 35 s = 4 half life
Therefore 45 g after first half life = 45 x1/2 =22.5 g
22.5 g after second half life = 22.5 x 1/2 =11.25 g
11.25 g after third half life = 11.25 x 1/2 = 5.625 g
5.625 after fourth half life = 5.625 x 1/2 = 2.813
therefore 2.813 g of Scandium 47 remains unchanged.
